I am a beginner in website creation and know a little bit here or there about coding but I am absolutely confused with the errors I am getting on my website. I am trying to test how the Square payment module works after following the instructions provided on how to set up. The extension is enabled and set up correctly however, after attempting to process a payment I received 2 different errors! How do I fix this so this does not continue happening. Also, although I received an error the payment still processes in the back-end as I received an email from Square however OpenCart does not tell me (who is acting as a customer) that the payment or order went through... I have also attached screenshots for review. Thank you!

I am getting 2 errors. The first one is when I do not check the save card box it says my ZIP is wrong. The second one is when I leave the box unchecked, the payment goes through (as I tested using my actual bank card which is why it is red for security).

I haven't used the built-in Square payment extension much, but if you end up not being able to get it working, I do have a Square Payment Gateway extension that works without issue on OpenCart 3. It also predates the built-in one, so it has a longer period of active development.

If you're not looking for a commercial solution, you might try downloading the latest Square files from the github directory, and see if those work. I'd make sure to backup the original files, though, since using github files can always be chancy (since they're constantly being modified).